| Our country is located in a place where the earthquake is happened frequently,which causes a great damage to the architectural constructions, while for the mostdamaged constructions meet the standard of the seismic design criterion, no matterfrom the perspective of the urgency of settling down the residents or the economy torebuild after the damage,“reinforcing and restoring” are more reasonable than razedand rebuilt. And the difference between repair of earthquake-damaged frame jointsand seismic repair of earthquake-damaged structure is that the later is under thecircumstance that the damaged constructions dissatisfy with the requirements forfortification against earthquake, so that to reinforce in order to improve theirearthquake resistance; while the former is to return to the original seismic capacity orimprove its seismic capacity through reinforcing the damage in the premise of damageby the earthquake. It is of great significance to study the seismic performance ofconcrete-filled square steel tubular column which is reinforced after damaged for itenjoying an excellent mechanical property and seismic capacity.This paper aims at studying on the seismic property of the concrete-filled squaresteel tubular column which is reinforced after damaged and the research work andachievements related mainly involve:(1) Propose a plan of reinforcing the steel-enveloped. One half scaled models offive lateral joints in concrete-filled square steel tube frame were designed andmanufactured. The seismic damaged load by simulated earthquake and rehabilitationand the destructions tests under the load on three of models were carried; there areadditional two experiments as the objects of reference, which one is to be reinforced,and the other is not to be reinforced, and then, conduct the rehabilitation and thedestructions tests separately.(2) The seismic property of the concrete-filled square steel tubular columnconnections after steel-enveloped reinforcement. Through analyzing the data from theexperiments to the five connections, namely load displacement, displacement-thehysteresis curves, skeleton curves, ductility, dissipative ability, ultimate strength andstiffness degradation, etc, this experiment is to study the seismic performance of thesteel-enveloped structure. Connection has a significant effect on increasing theultimate bearing capacity and improving the displacement ductility and the seismicproperty of the connections, which certify the validity of the steel-envelopedreinforcement. Reinforced steel-enveloped structure meets the strong column-weak connections requirement of seismic ductility and the dissipative ability of deformation,also the failure modes of all connections are the bendingfailure of beam. The reinforcement is benefit to the anti-seismic of the structure as awhole. The steel-enveloped can protect the concrete in the steel pipe well to avoid thesecond damage after it’s damaged, and under the certain earthquake-damagedcondition, the seismic performance of reinforced connections can reach or evenexceed the level of their original.(3) Calculate and analyze the bearing capacity of the connections reinforced bysteel-enveloped after damaged. Considering the effect of the reinforcement and basedon the current technical regulations of the concrete-filled rectangle steel tubularcolumn connections, bearing capacity design formulas considering initial damage ofCFST frame joints strengthened with steel-enveloped are given in the paper. |
PDF Full Text Request